Patents by Inventor Randy J. Vander Heyden

Randy J. Vander Heyden has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 4617554
    Abstract: A multi-key keyboard is scanned at high speed in such a manner as to substantially reduce erroneous key entries caused by the simultaneous engagement of more than one key. A keyboard processor determines which key is down by sequential scanning of the keyboard, encodes the selected key and sends this code to a master processor, or CPU. A 2-key lockout scanning approach is employed wherein keyboard scanning stops when two keys are selected simultaneously. Scanning is resumed when either one or both of the first two keys are released. By limiting simultaneous key engagement detection to two keys, system complexity and cost are kept within reasonable limits while insuring against erroneous key entries. Detecting and storing the key engagement sequence permits a selected special function, e.g., automatic key repeat, to be applied to the last selected key rather than to an earlier selected, but simultaneously engaged, key.
    Type: Grant
    Filed: August 26, 1983
    Date of Patent: October 14, 1986
    Assignee: Zenith Electronics Corporation
    Inventors: Charles A. Krause, Randy J. Vander Heyden